1. The Field of the Invention
The present invention relates to apparatuses used to clean medical devices. In particular, the present invention relates to a brush for safely and effectively cleaning the interior passageway of medical devices such as hemodialysis tubes, catheters, feeding tubes, and venous lines, without necessitating removal of the medical device from the patient.
2. The Relevant Technology
Various types of tubular medical devices have been employed in the medical field to perform a broad range of important functions. For example, catheters are commonly employed to carry various bodily fluids, including but not limited to, abscess fluids, urinary fluids, or biliary fluids. Other such medical devices include feeding tubes, used to provide nutrition to a patient, hemodialysis tubes, and venous lines.
Many of these medical devices are used in long-term treatments. It is important that the interior passageway in these medical devices remain unobstructed. Accordingly, various cleaning devices have been developed which are intended to remove matter such as particles, residues, and the like, which may collect in the interior passageway, or other portions, of the medical device. Some types of medical devices include a retention string which resides inside the device and is used to control the device during placement. One problem associated with such retention string arrangements is that residue or particles may build up on the retention string itself. Such buildup may lead to uneven, reduced, or obstructed flow in the tubular medical device. Obstructed or limited flow may extend the recovery time of a patient, resulting in the potential for further complications or infections. For example, an infection may cause complications in the patient""s treatment leading to sickness or even death. These problems are exacerbated in those cases where the medical device must be kept in place for a relatively long period of time.
Presently, many of these types of medical devices are periodically exchanged for a new instrument. Typically, the life of the medical device is limited by buildup in the interior passageway. As a result, after a certain amount of time, the medical device is removed and discarded and a new device is then inserted. Inserting a new medical device however, often implicates additional risks of inducing infection. In addition, the replacement of the medical device increases the overall cost to the patient. Thus, each replacement of the medical device implicates a variety of undesirable effects, including increased pain to the patient, increased expenses, and increased potential for inducing an infection which could jeopardize the health of the patient.
As suggested earlier, various specialized instruments have been developed for use in conjunction with tubular type medical devices. However, as discussed below, none of these devices are designed to permit cleaning of the tubular medical device while the medical device is attached to and fluidly connected to the patient.
One example of such a device is a cytology brush such as is used to collect cells for analysis. The cytology brush is basically an elongated brush which includes soft bristles. The brush is passed through an endoscope or coaxial catheter and pushed so that the bristles brush over the end wall of the duct to displace cells from the duct wall. Some of the cells are captured in the bristles. By design, cytology brushes are intended to collect cells and are not structurally equipped to apply the scrubbing forces necessary for removal of particles, residue, or the like from the interior passageway of a medical device.
A brush apparatus is also available that is used to detect whether a catheter is a cause of an infection in a patient, without necessitating removal of the catheter from the patient to perform the detection process. Typically, the apparatus includes a wire handle, brush, and a protective, microbially impervious bag disposed over the handle and brush. The device is used by advancing the brush in the catheter and simultaneously removing it from the protective bag. After the sample has been obtained, the brush is retracted. Once the brush is fully retracted, the wire to which the brush is attached is clipped and the brush is placed into the bag, or a vial.
Yet another type of brush that is available is a motorized brush that is inserted through a catheter, over a guidewire, into a blood vessel. In use, the brush extends beyond the catheter and is used to break up blood clots in the blood vessel.
Finally, a brush-tipped catheter is available which includes a biopsy brush that comprises a plurality of bristles that extend from the distal end of a catheter sheath itself. Such biopsy brushes are typically employed in the context of peripheral transbronchial biopsies to obtain samples.
In view of the foregoing problems and shortcomings, it would be an advancement in the art to provide a brush that facilitates, among other things, safe and effective in situ cleaning of tubular medical devices such as hemodialysis tubes, catheters, feeding tubes, drainage tubes, venous lines, and the like.
The present invention has been developed in response to the current state of the art, and in particular, in response to these, and other, problems and needs that have not been fully or adequately resolved by currently available brushes. Briefly summarized, embodiments of the present invention provide an improved brush which facilitates, among other things, safe and effective cleaning of passageways defined by various medical devices without necessitating removal of the medical device from the patient or otherwise interrupting fluid communication between the patient and the medical device.
Embodiments of the present invention are well suited for use in the context of the cleaning of medical devices such as hemodialysis tubes, catheters, feeding tubes, drainage tubes, venous lines, and the like. However, it will be appreciated that embodiments of the present invention are suitable for use in any application or environment where it is desired to implement safe and effective in situ cleaning of a medical device defining one or more passageways in communication with, or otherwise connected to, a patient.
In one embodiment of the present invention, a brush is provided that includes an atraumatic tip comprising a core wire, preferably composed of a memory alloy such as NiTiNOL (Nickel Titanium Naval Ordnance Laboratory), and ground so that the core wire tapers from a relatively larger outside diameter at its proximal end to a relatively smaller outside diameter at its distal end. The proximal end of the core wire is preferably substantially flattened so as to overlap with a braided fill wire, discussed below. Disposed about the core wire is a coil, preferably comprising gold-plated tungsten. A suitable epoxy bonds the coil to the hollow core wire and to a distal connector sleeve, discussed below, within which the proximal end of the core wire is received. Finally, a bulb, preferably comprising medical grade epoxy, is disposed about the coil at the distal end of the core wire.
As suggested above, the atraumatic tip is joined to a fill wire, preferably comprising a plurality of braided wires, which includes a fill section comprising a plurality of bristles, or fill, preferably comprising nylon or the like. The braiding facilitates, among other things, a high degree of flexibility in the fill wire. The flattened end of the core wire is made to overlap with the distal end of the fill wire, which preferably comprises stainless steel, and the two are retained in place by way of the distal connector sleeve, preferably comprising stainless steel. Preferably, the distal connector sleeve is resistance welded to the proximal end of the core wire and to the distal end of the fill wire. The brush bristles, or fill, are incorporated during the braiding of the wire and the outside diameter of the fill section preferably increases from the distal end of the fill wire to the proximal end of the fill wire. The proximal end of the fill wire is joined to a shaft, preferably comprising NiTiNOL, by way of a proximal connector sleeve that is resistance welded to the fill wire and the shaft. Preferably, the proximal connector sleeve comprises stainless steel.
Finally, an inner sheath, preferably comprising a high temperature heat shrink paraffinic polymer, such as polytetrafluoroethylene (PTFE), is shrink wrapped around the portion of the brush extending from the proximal connector sleeve to the proximal end of the fill section of the fill wire. The inner sheath, in turn, is covered with an outer sheath that covers the entire shaft and extends up to the proximal end of the fill section. Preferably, the outer sheath, like the inner sheath, comprises PTFE (such as Teflon(copyright)).
In operation, the atraumatic tip of the brush is inserted into the passageway defined by a catheter, drainage tube, venous tube, or other medical device and pushed along the passageway until the fill is in position for cleaning. The flexibility imparted by the core wire, tungsten coil, fill wire, and NiTiNOL shaft permits the brush to readily negotiate the passageway defined by the medical device. Further, the tapered core wire and coil of the atraumatic tip are effective in facilitating cleaning of the passageway while also minimizing harm to the patient or to the medical device in which the brush is disposed.
Further, the downward taper of the fill, toward the distal end of the atraumatic tip, enables the distal end of the fill section to readily enter very small openings, such as may be encountered where there is substantial residue or a blockage of the passageway defined by the medical device. As the atraumatic tip is gradually worked into the blockage, the tapered outside diameter of the proximal end of the fill section is effective in enlarging the opening to the point that the blockage is ultimately removed. The bulb on the distal end of the atraumatic tip section further cooperates with the fill wire section to dislodge blockages and the like that are present in the passageway defined by the medical device.
Further, the inner sheath provides for a smooth transition from the braided fill wire to the distal connector sleeve and also serves to help prevent kinks in the fill wire as the fill section is worked through the blockage. Finally, the outer sheath further contributes to the ease with which the brush negotiates the passageway by substantially covering the fill wire and by implementing a transition between the fill wire and the shaft, thus providing the brush with a smooth, continuous outside coating of substantially constant diameter.
These and other advantages and features of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of the invention as set forth hereinafter.